1. Field of the Invention
The present invention relates to a method for the preparation of high-quality leached fish flesh from the fish of various kinds of fresh fish and frozen fish.
2 Description of the Prior Art
In the industry of fish-paste products, the water rinsing process of fish is extremely important. The purpose of the water rinsing process is to remove dyestuff, smelling components, muscle-forming proteins and fats from the fish, but the most important purpose thereof is to improve the gel formation ability of the fish.
In the conventional water rinsing process, cold water or a cold sodium bicarbonate liquid is added to segments (3 to 8 mm.sup.2) of the fish, the amount of the water or liquid being 5 to 8 times as much as that of the segments. Afterward, the immersion of the segments therein is kept up for a period of 20 to 30 minutes while stirred at times, followed by dehydration. This operation is repeated 2 to 5 times. In this case, the fish which can be used as raw material fish are limited to light flesh of fresh fish, and dark flesh and frozen fish can scarcely be utilized. The reason is that the removal ratio of the fats and dyestuffs from dark flesh is low. In the conventional technique, it is difficult to obtain the high-quality leached fish flesh from fish containing a great deal of the dark flesh and fats such as sardines and mackerel. Particularly, with regard to frozen sardines, even if light flesh thereof only is used, the improvement of the gel formation ability can barely be achieved by the conventional water rinsing process.
A process for disintegrating organic material into its main nutritional constituents of fats, proteins, salts, nucleotides and insoluble solids, and separating them for nutritional use is described in a patent issued to Ehrensvard, U.S. Pat. No. 3,491,080. This process comprises adding to organic material a solution of calcium and hydroxide ions in water, blending the mixture to extract the nutritional constituents and separating the resulting extracted constituents by centrifugation and precipitation. In the Ehrensvard process, calcium hydroxide, the source of hydroxyl ions, remains largely undissolved and it releases hydroxyl ions to the solution as the ions are consumed during the extraction. This maintains in the process, a relatively low hydroxyl ion concentration at a pH of about 11-12 and is an unsuitable pH level for the instant invention because high gel-formation ability is lost. Such a disability is readily understandable since it was not the purpose of Ehrensvard to create a product having high gel-formation ability. As will be hereinafter made apparent, the instant inventor, by a unique process of leaching fish flesh using a phospate/sodium bicarbonate solution as a leaching liquid obtains a dehydrated fish flesh which has a high gel formation ability. This process and product allows the instant inventor to produce frozen Surimi which has a sufficient gel-formation ability for the manufacture of Kamaboko, a fish jelly having a high concentration of protein.